Use of additional cooling of oil transformers in the joint operation of thermoelectric converters and ground-coupled heat exchangers

Transformers belong to the main equipment of power plants, raising, lowering and distribution substations, as well as various types of converter devices. In the process of operating oil transformers, damage or defects can occur, the timely detection of which enables taking measures to prevent their furtherance and to keep the equipment intact. Severe consequences are caused by damage to the windings and main insulation of the transformers as it might bring about malfunctions in the cooling system. Existing cooling devices are not always efficient. We have developed a complementary cooling system for power transformers with thermoelectric converters. The operating principle of the device is based on the following: at night, when the ambient temperature is the lowest, water ice is produced the melting of which keeps the transformer oil cold in the hottest daytime. Two operating states of the developed device are described. We also herein present a mathematical description of the water cooling process. We have analyzed the results of studies consisting in evaluating the alteration in the heat flow drawn by vertical ground-coupled heat exchangers. The results of the research show it is possible to use the system for thermoelectric module- and VGHE-enabled liquid cooling of power oil transformers that will allow to draw up to 50% of heat at peak thermal loads, whereas the transformer power is expected to increase by 25-40% depending on the specifications.